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Preoperative risk stratification by adenosine thallium 201 single-photon emission computed tomography in patients
M G Koutelou1, P J Asimacopoulos, J J Mahmarian
1Department of Internal Medicine, Baylor College of Medicine, Methodist Hospital, Houston, Texas 77030, USA.
Background:
Adenosine perfusion scintigraphy is a powerful technique for diagnosing coronary artery disease and risk stratifying patients with recent myocardial infarction.
Methods And Results:
We investigated the use of adenosine 201Tl tomography to risk stratify 106 patients undergoing vascular arterial reconstruction consisting of lower limb arterial grafting in 44, aortic aneurysmectomy in 36, and carotid endarterectomy in 26 patients. Abnormal tomograms occurred in 57 patients (54%), 47 (82%) of whom had reversible perfusion defects. There were three postoperative deaths, all in the group that underwent aortic aneurysmectomy. Another patient with an aortic aneurysm had unstable angina and one patient who underwent lower limb arterial surgery had pulmonary edema after surgery. No patient without transient defects had an event (negative predictive value 100%). Cardiac events occurred only in patients with transient perfusion defects. However, only 5 of 47 such patients had events (positive predictive value 11%). The perfusion defect size (23% +/- 14% vs 8.9% +/- 135; p = 0.034) and the ischemic fraction (20% +/- 16% vs 5.6% +/- 8.9%; p = 0.009) were 2.5- and 3.5-fold larger, respectively, in patients with than in those without events. A history of diabetes mellitus or previous infarction did not enhance the predictive value of the test.
Conclusion:
Thus absence of reversible hypoperfusion during adenosine scintigraphy ensures virtual absence of postoperative cardiac events. Patients undergoing aortic aneurysmectomy may be targeted preferentially for risk-stratification strategies in the future.